Charging circuit

Abstract

To provide a charging circuit which is reduced in size and cost by installing an AC charging function.SOLUTION: An AC connector to which an external device is connected, a 2INV inserted between a first connection point at which a source of a first 2INV upper-arm switching device (high-side SW device) of the 2INV is connected to a positive electrode line of a battery and a second connection point at which a source of a second 1SW upper-arm switching device (high-side SW device) of the high-side SW device is connected to the positive electrode line; A first 2INV inserted between the second connection point and a third connection point at which a source of an upper SW device of a third phase of the first 2SW is connected to the positive electrode line, a second 3SW inserted between the first connection point and the AC connector, a third 4SW inserted between the second connection point and the AC connector, a fourth 5SW inserted between the third connection point and the AC connector, and a fifth 6SW inserted between the AC connector and the negative electrode line of the battery.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a charging circuit for use in a system that drives a motor with two inverters. [Background technology]

[0002] Patent Document 1 discloses a dual inverter having a first inverter and a second inverter with output terminals commonly connected to one motor. This dual inverter compares the magnitude of an overall voltage command for driving the motor with the magnitude of a DC power supply voltage commonly applied to the first inverter and the second inverter, and based on the comparison result generates a first voltage command for the output of the first inverter and a second voltage command for the output of the second inverter, thereby improving the output efficiency of the inverters and the motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-085914 Summary of the Invention [Problem to be solved by the invention]

[0004] The dual inverter described in Patent Document 1 does not consider where to install the AC charging function. Therefore, there is room for consideration of a method for installing the AC charging function in order to reduce the size and cost of the charging circuit.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a charging circuit that is miniaturized and inexpensive by suitably providing an AC charging function. [Means for solving the problem]

[0006] In order to solve the above-described problems, one aspect of the disclosed technology is a charging circuit used in a system that drives a motor having three-phase windings whose neutral points are uncoupled by a first inverter connected to a first battery so as to be able to charge and discharge power and a second inverter connected to a second battery so as to be able to charge and discharge power, the charging circuit comprising: an AC connector for connecting an external device so as to be able to exchange power; a first switch inserted between a first connection point at which a source terminal of an upper arm switching element of a first phase of the second inverter is connected to a positive line of a second battery and a second connection point at which a source terminal of an upper arm switching element of a second phase of the second inverter is connected to the positive line; a second switch inserted between the second connection point and a third connection point at which a source terminal of an upper arm switching element of a third phase of the second inverter is connected to the positive line; a third switch inserted between the first connection point and the AC connector; a fourth switch inserted between the second connection point and the AC connector; a fifth switch inserted between the third connection point and the AC connector; and a sixth switch inserted between the AC connector and the negative line of the second battery. [Effects of the Invention]

[0007] According to the charging circuit of the present disclosure, the inverter switching elements, motor windings, and smoothing capacitors can be utilized for AC charging operations, thereby enabling the charging circuit to be made smaller and less expensive. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a motor drive system including a charging circuit according to an embodiment of the present disclosure; [Figure 2] A diagram showing the connection status of each switch when AC charging the first battery from an external power supply (three-phase input) [Figure 3] A diagram showing the connection status of each switch when AC power is supplied from the first battery to an external device [Figure 4] Diagram showing the connection status of each switch when AC output from the first battery to the outlet inside the vehicle [Figure 5] A diagram showing the connection status of each switch when AC charging the first battery from an external power supply (single-phase input) [Figure 6] FIG. 1 is a schematic configuration diagram of an application example of a motor drive system including a charging circuit according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Embodiment> [composition] Fig. 1 is a diagram showing an example of a schematic configuration of a motor drive system 1 including a charging circuit according to an embodiment of the present disclosure. The motor drive system 1 illustrated in Fig. 1 includes a first battery 11, a second battery 12, a first inverter 110, a second inverter 120, and an electric motor 130, and is a system that drives the electric motor 130 using a dual inverter consisting of the first inverter 110 and the second inverter 120. The motor drive system 1 of this embodiment includes an AC connector 200 and a plurality of switches 201 to 206 as components of the charging circuit.

[0010] The first battery 11 and the second battery 12 are secondary batteries configured to be rechargeable, such as lithium-ion batteries, and function as DC power sources for the first inverter 110 and the second inverter 120. By switching between multiple switches 13 to 18, the first battery 11 and the second battery 12 are appropriately supplied to the first inverter 110 and the second inverter 120 as independent parallel batteries or as a single series battery. Furthermore, the first battery 11 (and also the second battery 12) can be charged using a DC charger 30 and multiple switches 31 and 32.

[0011] The voltage of the first battery 11 is suitably smoothed by a smoothing capacitor 141. The voltage of the second battery 12 is suitably smoothed by a smoothing capacitor 142.

[0012] The first inverter 110 is a three-phase inverter that provides three-phase voltages and currents to the electric motor 130, and is configured with a pair of an upper arm switching element 111 and a lower arm switching element 114 in the first phase, a pair of an upper arm switching element 112 and a lower arm switching element 115 in the second phase, and a pair of an upper arm switching element 113 and a lower arm switching element 116 in the third phase. These switching elements 111 to 116 can be made of MOS (metal oxide semiconductor) transistors or the like. The source terminals of the upper arm switching elements 111 to 113 of each phase are connected to the positive line (high potential side) of the first battery 11. The drain terminals of the lower arm switching elements 114 to 116 of each phase are connected to the negative line (low potential side) of the first battery 11. The connection points between the drain terminals of the upper arm switching elements 111 to 113 and the source terminals of the lower arm switching elements 114 to 116 in each phase are connected to one of three-phase windings 131 to 133 of the electric motor 130, respectively.

[0013] The first inverter 110 converts DC power from the first battery 11 and / or the second battery 12 into AC power and outputs (discharges) it to the electric motor 130. The first inverter 110 can also convert AC power input via the electric motor 130 into DC power and input (charge) it to the first battery 11. Such input / output (charging / discharging) actions of the first inverter 110 are appropriately controlled by control signals (such as PWM signals) that are individually applied to the gate terminals of the switching elements 111 to 116 by a control circuit (not shown).

[0014] The second inverter 120 is a three-phase inverter that provides three-phase voltage and current to the electric motor 130. It has a structure in which a pair of an upper arm switching element 121 and a lower arm switching element 124 is provided in the first phase, a pair of an upper arm switching element 122 and a lower arm switching element 125 is provided in the second phase, and a pair of an upper arm switching element 123 and a lower arm switching element 126 is provided in the third phase. MOS transistors or the like can be used for these switching elements 121-126. During normal operation (switches 16 and 153: ON, switches 151 and 152: OFF), the source terminals of the upper arm switching elements 121-123 of each phase are connected to the positive line (high potential side) of the second battery 12. The drain terminals of the lower arm switching elements 124-126 of each phase are connected to the negative line (low potential side) of the second battery 12. Furthermore, the connection points between the drain terminals of the upper arm switching elements 121 to 123 and the source terminals of the lower arm switching elements 124 to 126 in each phase are connected to one of three-phase windings 131 to 133 of the electric motor 130, respectively.

[0015] The second inverter 120 converts DC power from the first battery 11 and / or the second battery 12 into AC power and outputs it to the electric motor 130. The second inverter 120 can also output AC power input via an AC connector 200 (described later) to the electric motor 130. Such output behavior of the second inverter 120 is appropriately controlled by control signals (such as PWM signals) that are individually applied to the gate terminals of the switching elements 121 to 126 by a control circuit (not shown).

[0016] The source terminals of the upper arm switching elements 111-113 of the first inverter 110 and the source terminals of the upper arm switching elements 121-123 of the second inverter 120 are connected via switches 151 and 152, such as semiconductor switches. The source terminals of the upper arm switching elements 121-123 of the second inverter 120 are connected to the second battery 12 via switch 153.

[0017] Electric motor 130 is a three-phase AC motor having three-phase windings 131 to 133 with uncoupled neutral points. Winding 131 is connected between a connection point between upper arm switching element 111 and lower arm switching element 114, which constitute the first phase of first inverter 110, and a connection point between upper arm switching element 121 and lower arm switching element 124, which constitute the first phase of second inverter 120. Winding 132 is connected between a connection point between upper arm switching element 112 and lower arm switching element 115, which constitute the second phase of first inverter 110, and a connection point between upper arm switching element 122 and lower arm switching element 125, which constitute the second phase of second inverter 120. The winding 133 is connected between the connection point between the upper arm switching element 113 and the lower arm switching element 116, which constitute the third phase of the first inverter 110, and the connection point between the upper arm switching element 123 and the lower arm switching element 126, which constitute the third phase of the second inverter 120.

[0018] The charging circuit includes an AC connector 200 and a plurality of switches (SW) 201-206 in addition to a first inverter 110, a second inverter 120, and an electric motor 130.

[0019] The AC connector 200 is a component for electrically connecting a predetermined external device to the motor drive system 1. For example, if the external device is a power supply facility that supplies AC power (such as an AC charging stand), the AC connector 200 functions as an AC inlet. On the other hand, if the external device is an external device that consumes AC power (such as a V2H in-home power supply), the AC connector 200 functions as an AC outlet.

[0020] The multiple switches 201 to 206 are elements or components that can be switched between an electrically conductive state and an electrically cut-off state by a control circuit (not shown). The switch 201 (first switch) is inserted between a point where the source terminal of the upper arm switching element 121 of the first phase of the second inverter 120 is connected to the positive line of the second battery 12 (hereinafter referred to as the "first connection point") and a point where the source terminal of the upper arm switching element 122 of the second phase of the second inverter 120 is connected to the positive line of the second battery 12 (hereinafter referred to as the "second connection point"). The switch 202 (second switch) is inserted between the second connection point and a point where the source terminal of the upper arm switching element 123 of the third phase of the second inverter 120 is connected to the positive line of the second battery 12 (hereinafter referred to as the "third connection point"). The switch 203 (third switch) is inserted between the first connection point and the AC connector 200. A switch 204 (fourth switch) is inserted between the second connection point and the AC connector 200. A switch 205 (fifth switch) is inserted between the third connection point and the AC connector 200. A switch 206 (sixth switch) is inserted between the AC connector 200 and the negative line of the first battery 11 and / or the second battery 12.

[0021] [Specific example] 2 to 5, several specific examples of charging / power supply using AC connector 200 and multiple switches 201 to 206 will be described.

[0022] Fig. 2 is a diagram [during AC charging (three-phase input)] that explains the connection state of each switch when three-phase AC power supply equipment 300 is connected to AC connector 200 functioning as an AC inlet and first battery 11 is charged with power supplied from three-phase AC power supply equipment 300. In Fig. 2, in motor drive system 1, switches 16, 17, 19, 203, 204, 205, and 206 are set and controlled to a conductive state (ON), and switches 15, 18, 20, 151, 152, 153, 201, and 202 are set and controlled to a disconnected state (OFF).

[0023] By setting and controlling the connection state of each switch as shown in Figure 2, the power supplied from the three-phase AC power supply equipment 300 can be used to charge the first battery 11 while performing power factor adjustment (power factor correction) and charging power adjustment, utilizing the switching elements 121 to 126 of the second inverter 120, the windings 131 to 133 of the electric motor 130, the switching elements 111 to 116 of the first inverter 110, and the smoothing capacitor 141.

[0024] 3 is a diagram illustrating the connection state of each switch when an external device 400 is connected to AC connector 200 functioning as an AC outlet and power from first battery 11 is supplied to external device 400 [during external AC power supply]. External device 400 is a device or facility that consumes power, and examples include an electrical appliance that requires an AC power source, a household outlet connected via V2H, and an electric vehicle (a vehicle other than the vehicle equipped with motor drive system 1). In FIG. 3, motor drive system 1 is configured such that switches 16, 17, 19, 203, 204, 205, and 206 are set to a conductive state (ON), and switches 15, 18, 20, 151, 152, 153, 201, and 202 are set to a disconnected state (OFF).

[0025] By setting and controlling the connection state of each switch as shown in Figure 3, the power of the first battery 11 can be supplied to the external device 400 via the smoothing capacitor 141, the switching elements 111 to 116 of the first inverter 110, the windings 131 to 133 of the electric motor 130, and the switching elements 121 to 126 of the second inverter 120.

[0026] 4 is a diagram illustrating the connection state of each switch when power from first battery 11 is supplied to interior outlet 500 provided in the interior of a vehicle equipped with motor drive system 1 (during AC power supply from interior outlet). When interior outlet 500 is installed in the vehicle, switch 211 is pre-inserted between the first connection point and one terminal of interior outlet 500, and switch 212 is pre-inserted between the negative line of the battery and the other terminal of interior outlet 500. In FIG. 4, in motor drive system 1, switches 16, 17, 19, 211, and 212 are set and controlled to a conductive state (ON), and switches 15, 18, 20, 151, 152, 153, 201, 202, 203, 204, 205, and 206 are set and controlled to a disconnected state (OFF).

[0027] By setting and controlling the connection state of each switch as shown in Figure 4, the power of the first battery 11 can be output (supplied) to the vehicle interior outlet 500 via the smoothing capacitor 141, each switching element 111-116 of the first inverter 110, windings 131-133 of the electric motor 130, and each switching element 121-126 of the second inverter 120.

[0028] Fig. 5 is a diagram [during AC charging (single-phase input)] that explains the connection state of each switch when single-phase AC power supply equipment 600 is connected to AC connector 200 functioning as an AC inlet and first battery 11 is charged with power supplied from single-phase AC power supply equipment 600. In Fig. 5, in motor drive system 1, switches 16, 17, 19, 201, 202, 203, 204, 205, and 206 are set and controlled to a conductive state (ON), and switches 15, 18, 20, 151, 152, and 153 are set and controlled to a disconnected state (OFF).

[0029] By setting and controlling the connection state of each switch as shown in Figure 5, the power supplied from the single-phase AC power supply equipment 600 can be used to charge the first battery 11 while performing power factor adjustment (power factor correction) and charging power adjustment, utilizing the switching elements 121 to 126 of the second inverter 120, the windings 131 to 133 of the electric motor 130, the switching elements 111 to 116 of the first inverter 110, and the smoothing capacitor 141.

[0030] [Application example] FIG. 6 shows an example of an applied schematic configuration of a motor drive system 1 including a charging circuit according to this embodiment.

[0031] As illustrated in FIG. 6, an additional component 160 such as a leakage detection / cutoff mechanism or a noise filter may be inserted between the first battery 11 and the second battery 12 and the first inverter 110 and the second inverter 120 (i.e., before the smoothing capacitors 141 and 142).

[0032] As illustrated in FIG. 6, additional components 220 such as a leakage detection / cutoff mechanism, a noise filter, and an additional smoothing capacitor may be inserted between switch 203 and the first connection point, between switch 204 and the second connection point, between switch 205 and the third connection point, and between switch 206 and the negative line of the battery (i.e., in the upstream stage of each of switches 203 to 206).

[0033] <Actions and Effects> As described above, the motor drive system 1 including the electrical circuit according to one embodiment of the present disclosure employs a configuration in which, in the second inverter 120, the first switch 201 is inserted between the first connection point where the upper arm switching element 121 of the first phase is connected to the positive line and the second connection point where the upper arm switching element 122 of the second phase is connected to the positive line, the second switch 202 is inserted between the second connection point and the third connection point where the upper arm switching element 123 of the third phase is connected to the positive line, the third switch 203 is inserted between the first connection point and the AC connector 200, the fourth switch 204 is inserted between the second connection point and the AC connector 200, the fifth switch 205 is inserted between the third connection point and the AC connector 200, and the sixth switch 206 is inserted between the AC connector 200 and the negative line of the battery.

[0034] This configuration allows the switching elements of the first inverter 110 and the second inverter 120, the windings 131 to 133 of the electric motor 130, and the smoothing capacitor 141 to be utilized for AC charging operations, thereby making it possible to reduce the size and cost of the charging circuit. [Industrial Applicability]

[0035] The charging circuit of the present disclosure can be used in a system that drives a motor using two inverters. [Explanation of symbols]

[0036] 1 Motor drive system 11 Battery No. 1 12 Second Battery 110 1st inverter 111~116 Switching elements 120 Second inverter 121~126 Switching elements 130 electric motor 131~133 Three-phase winding 141, 142 smoothing capacitor 151~153, 201~206 Switches 160, 220 additional configuration 200 AC connector 300 Three-phase AC power supply equipment 400 External device 500 In-car power outlet 600 Single-phase AC power supply equipment

Claims

[Claim 1] A charging circuit used in a system that drives a motor having three-phase windings with a neutral point uncoupled by a first inverter connected to a first battery so as to be able to charge and discharge power, and a second inverter connected to a second battery so as to be able to charge and discharge power, an AC connector for connecting an external device so as to be able to receive and transmit power; a first switch inserted between a first connection point at which a source terminal of an upper arm switching element of a first phase of the second inverter is connected to a positive line of the second battery, and a second connection point at which a source terminal of an upper arm switching element of a second phase of the second inverter is connected to the positive line; a second switch inserted between the second connection point and a third connection point at which a source terminal of an upper arm switching element of a third phase of the second inverter is connected to the positive line; a third switch inserted between the first connection point and the AC connector; a fourth switch inserted between the second connection point and the AC connector; a fifth switch inserted between the third connection point and the AC connector; a sixth switch inserted between the AC connector and the negative line of the second battery.

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